Such control processes are known under the terms of CATS control and disclosed for power transistors in “CATS Control: Assessment of the Robustness and Application to the Servo-Control of Closure”, N. IDIR, H. SAWEZYN, J. J. FRANCHAUD, R. BAUSIERE, University of Lille 1, Laboratoire L2EP.
These CATS control processes have been developed to control the derivative di/dt of the intensity of the current circulating between the collector and the emitter of the power transistor as well as the variations of the derivative dv/dt of the voltage at the terminals of the power transistor.
This object is attained by applying a plurality of different successive voltages between the beginning and the end of the commutation process of the transistor. Among this succession of voltages, at least one, so-called braking voltage has an intermediate value different from those adapted to maintain the power transistor in the conducting and non-conducting states. The value of this braking voltage is chosen so as to brake commutation of the power transistor and consequently to limit and control the variations of the derivatives di/dt and dv/dt respectively upon closure and upon opening of the power transistor. The period during which this braking voltage is applied on the control electrode of the power transistor must be controlled with precision in order to limit the losses of commutation, i.e. the power consumed during each commutation. To that end, the end of the application of this braking voltage is automatically controlled when one or more conditions of passage are satisfied. For example, in the afore-cited document, the end of the application of the braking voltage is automatically controlled if the voltage at the terminals of a diode mounted in anti-parallel position with respect to the power transistor is less than a predetermined threshold and if the derivative of this same voltage is less than another threshold.
However, in the event of dysfunction of the power transistor, the condition of passage for controlling the end of the application of the braking voltage can never be satisfied. Under these conditions, the control process remains blocked, this being translated by the maintaining of the braking voltage on the control electrode of the power transistor for an undetermined duration. At best, this situation leads to consuming energy unnecessarily and, at worst, to deteriorating the power transistor.
It is an object of the present invention to overcome this drawback by proposing a control process of the CATS control type of an electronic power component, in which the unnecessary consumption of energy or the deterioration of the component is avoided.